Hero meets Teacher
by OnionKing
Summary: Saitama finds himself in an unfamiliar town where he encounters a monster trying to blend in. However this is no ordinary monster. This is Koro-sensei the teacher.
Congradulations to Matsui Yuusei-sensei for completing Assassination Classroom. I seriously hope to see another of your works in the future.

This is something quick I whipped up for the heck of it. Some harmless fun.

Disclaimer: I do not own Assassination Classroom or One Punch Man.

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"Aah… Which city is this?" A certain bold individual was walking down the street in an unfamiliar street. He reached down and brushed his red cape out of the way so he could pull on the yellow jumpsuit that was slowly crawling up his ass making him a little more comfortable. For some reason he held the attention of everyone who walked passed him. He definitely stood out in this crowd. Saitama merely ignored the stares. He was here for one thing, and one thing only.

"OHO! Genos was right! There is a bargain around here!" He started excitedly jogging towards the nearby store where he spied a very very good clearance sale. The second he entered the busy store, he did a quick scan to see what exactly was the cheapest. The baldy's eyes almost bulged when he saw the 80% off Udon hidden in the back. The owner must have thought that using the 50% off rice section as a distraction would make it invisible to the customers eye, but Saitama was no normal customer. He grabbed a shopping basket, took a deep breath, and weaved through the other customers with ease making it passed them all and straight to the udon sale.

Saitama reached out with a portion of his actual speed. Enough to grab all the packs in a few seconds, but not fast enough to create a blast of wind that would alert other customers. The millisecond before his hand grasped every pack of udon, a yellow tentacle wrapped itself around the packs and yanked them away. Saitama narrowed his eyes slightly as he followed the last one back to its owner.

There stood a three metre tall monster doing its best to blend in. It had a large yellow swollen head with an abnormally blank face. It wore a black academic dress, and a small black square academic cap with a yellow tassel. Its black tie with a yellow crescent-shaped moon fluttered slightly as his tentacles retracted with great speed. No other customer noticed this, only Saitama saw it. The octopus monster thing paid for the udon and left the store. Saitama watched on a little concerned seeing a monster purchase food like a normal person. However there was something that Saitama couldn't forgive.

The monster took his udon.

Saitama once again weaved his way through the crowd, and left the store just before he saw the monster take off in a certain direction. Not missing a beat, Saitama leapt into the air.

XxX

"Nurufufu… Everyone will be pleased with this." Koro-sensei the monster assassin target teacher of class 3-A had a large grin on his face as he wrote up individual tests with two tentacles, held the udon he had just purchased for an amazing price with another, and used the rest to swat away the air increasing his wind resistance preventing damage from coming to the udon or test papers.

What Koro-sensei didn't expect, was a man in a yellow jumpsuit to appear beside him and try to punch him. His colour changed from his standard yellow to a shocked purple. A human had managed to catch up to him when he was travelling at Mach 5. This was not normal. He barely had enough time to avoid the punch, but the wind from the attack was enough to send him off course. In his panicked state he was unable to fly properly and ended up crashing into the mountain where his class was waiting for him. It wouldn't be long before lunch break was over, and he needed to finish creating these tests.

As he crashed to the ground, Koro-sensei used his tentacles to tuck the papers and udon into his outfit to shield them from both damage and dust. Using his elasticity, Koro-sensei crashed but then bounced righting himself preventing his bald attacker landing on top of him.

"Wha-wha-wha-WHAT ARE YOU DOING ATTACKING ME MID FLIGHT!?" The yellow teacher yelled at the yellow suited man. "ACTUALLY WHAT ARE YOU?!"

"I'm just a hero for fun." Saitama pulled on his red glove before preparing himself once again.

"A hero? Not an assassin?" Koro-sensei asked curiously. He was back to his normal yellow. "But you are here to assassinate me?"

Saitama tilted his head in confusion. Of course a hero would go after a monster.

"Nurufufu." Koro-sensei changed colour to mocking yellow and green stripes. "I accept any challenge from any willing… WAIT WAIT WAIT!" The now panicked purple teacher was forced to bend his head down to avoid another punch from the hero.

Saitama merely looked down at the deformed head of the monster, and started throwing more punches in its general direction. "Hey… Stop dodging."

"H-H-H-HOW RUDE! ATTACKING BEFORE I AM READY!" Koro-sensei disappeared from in front of Saitama and ran up the mountain.

"Why would I wait?" Saitama asked as he chased the monster. This monsters behaviour was unusual from what he was used to, but there have been many different types of monsters, so in a way this was not unusual. Okay no this is definitely unusual. The monster stopped running outside of an old wooden building, but what was strange was that there stood 27 kids and 2 adults who had just run out of the building wondering what was causing all of Koro-sensei's high speed movements.

"Everyone. Please return inside, lunch is almost over." Koro-sensei turned around to the oncoming hero and used his tentacles to guide the considerably slower Saitama into punching the ground. It's funny how a little addition to someone's force can completely change the direction of an attack, although Saitama didn't resist, he was going to stop his attack anyway. There were people who would be harmed from if this attack continued. This monster was using these people as a hostage. He would have to get a little serious if he was going to protect these people.

A certain red haired boy walked towards Saitama as he picked himself up and dusted off his clothes. "Who is this baldy?" The boy continually slapped Saitama's head.

"Oi… Stop that…" Saitama was getting annoyed by this brat.

"KARMA-KUN GET AWAY!" Koro-sensei wrapped his tentacles around Karma and pulled him away. It was at this moment everyone there realised, this was a dangerous situation.

"Who are you?" The adult in the black suit stepped forward while raising his gun pointing it at the newcomer.

"I'm Saitama the hero. You?" Satiama was confused. He was just here to kill the monster who took his udon, but now there were people trying to stop him. Karasuma lowered his gun.

"Ministry of Defence. I didn't know an assassin was coming today." Karasuma noted that Saitama's blank face didn't change at all since his arrival. "I have no intention of stopping you killing the target however I ask that you wait until class is finished for the day as to not interrupt the students learning."

Saitama tilted his head slightly. "Students?" The kids were all in a uniform but that would mean the monster was teaching a class. Saitama shrugged as he agreed. He had nothing else to do, and it would give him time to go back and do some more shopping. "Okay…" He said before walking off.

"Koro-sensei. Who was that?" The blue haired male student with his hair two pigtails asked.

"Never mind him, lunch break is over."

XxX

Saitama had gone back to the store to buy other stuff, however by the time he got back the store had sold out of everything cheap, so Saitama became incredibly annoyed as he walked back up the mountain. When he reached the top he sat against a tree as he watched the class unfold. The monster… Koro-sensei was somehow able to use afterimages to teach each individual classmate something different. Apparently there was a student who was a box with a girl on it. He wondered what that was about, but it wasn't important.

He watched as the teacher was individually helping every single student with every afterimage, which would take an incredible amount of logical thinking. Being able to individually divide his thoughts with each afterimage perfectly so as to not interrupt the individual students learning is something that Saitama wasn't sure he could do, even though the afterimage thing might be possible.

Saitama just sat there, and watched. He chased after the monster because it took his udon, but what he saw here was nothing more than a teacher.

And it would not be right to take a teacher away from his students.

This was the decision he had come to, and so he decided it was time to leave.

"Where are you going?" Saitama turned to see another afterimage appear behind him.

"Home…" He answered honestly. "You are no monster."

"I cannot let you leave so easily. I can see the look in your eyes." Koro-sensei turned to his sadness blue colour. "Please wait a moment."

Back in the class, Koro-sensei stopped making afterimages for all the students and appeared in front of the class. "I'm sorry everyone, but I have to leave. Irina-sensei will take over and teach English."

"Where are you going Koro-sensei?" The short green haired girl asked.

"I have business with the man from earlier. He needs me as a teacher." Koro-sensei then reappeared back in front of Saitama who did wait.

"What look?" Saitama's blank face questioned the incredibly emotive octopus.

"The thing about these tentacles of mine, when they assimilate properly, they ask you what it is that you desire. What I asked for is the same as what you wish…" Koro-sensei was once again his blue colour. "You have been strong for too long and miss what it was to be weak."

"Eeeh?" Saitama half-heartedly asked as he begun to scratch his ass. This octopus didn't know him that well.

"But that's no matter. You are not the type of person to get a lesson without the use of violence." Koro-sensei was once again yellow and green striped. His mood had changed completely from a melancholic state of mind to his normal cheery mode. "You will be unable to kill me even if you tried. So shall we?"

"Oho?" Saitama was fired up again. It appears this teacher has guts.

"Can you fly?"

"I can jump."

"Follow me."

The sound of two sonic booms shook the entire building. Everyone inside was amazed that the one they thought was human could keep up with the flying Koro-sensei.

XxX

"There are no people around for the nearest 100km, let's keep the fighting in this area." Koro-sensei waved all of his tentacles in front of him prepared for Saitama's assault. Both of them were breathing perfectly normal as if they hadn't just moved a ridiculous distance.

"Okay…" Saitama once again leapt forward to attack the teacher. However this time, Koro-sensei retaliated. Creating a sonic boom with his tentacles as they slammed into the oncoming Saitama was enough force to send the bald hero tumbling along the ground. A wide eyed Saitama stood back up. That actually hurt him. For the first time, Koro-sensei took the initiative and charged towards the hero. A barrage of tentacles charged at Saitama from different directions, Saitama didn't try to dodge as the attacks continued to slam into him, barely making him move.

Saitama could feel these attacks but they were not as strong as the first one. Bending backwards slightly, Saitama grabbed one of the oncoming tentacles then pulled on it to throw a punch at the main body, but it missed completely as Koro-sensei's body literally changed form making him hit nothing by air. Tentacles wrapped around Saitama's arms and did an uppercut with the remaining tentacles, this caused Saitama to lift off the ground slightly, then Koro-sensei repeated his attack. Again and again.

Koro-sensei is not strong. He has never been strong, the force of his attacks never come from his mass, but come from his acceleration. So the only way he is able to damage Saitama is when he is maxing his acceleration which he can only do when he is focused on a single direction. Attaching himself to Saitama like this was the easiest way of doing this.

That was until Saitama ribbed Koro-sensei off of his arm and threw him towards the ground. Before he hit the ground, Koro-sensei flew into the air to be above Saitama. Saitama had never tried this before, but he attempted to use the air as a platform to jump. The sheer force of his push was enough to launch him towards Koro-sensei. This got the octopus to panic and fly just short of his top speed away from the hero. This was not enough to escape as Saitama continued to pounce on the air after the teacher. However this time, Saitama had a massive grin on his face.

"This feeling…" Saitama spoke under his breath but was heard by the teacher, who turned around mid-flight and used his tentacle to meet Saitama. Not expecting such a fast attack, Saitama was sent flying away, but it didn't take long to right himself and once again charge at the octopus. This time Saitama dodged the oncoming attack by leaping slightly to the side, then used his whole body as a battering ram pushing the octopus towards the ground. Koro-sensei slammed into the ground, but pushed off it.

"Is this all you want? A good fight?" Koro-sensei once again wrapped his tentacles around Saitama's oncoming fist, but this time he threw the hero over his shoulder (if you could call it that) and straight into the ground. The teacher gave him no opportunity to stand as he sped down and started to fire consecutive cannon-like shots from his tentacles into the downed hero. "You have been too strong for too long, you forget why you became strong in the first place."

"I have not forgotten." Saitama grabbed a tentacle with the next attack, then pulled himself up. He slowly started wrapping the tentacle around his arms drawing Koro-sensei closer to him. The octopus started to change colour as he panicked. "I just no longer enjoy the fighting since it is always too easy."

Saitama head-butt the octopus, launching him across the plain they stood on. Saitama waited two seconds, before watching at Koro-sensei flew right back at him. The two of them started throwing consecutive punches at each other. Koro-sensei avoiding all of the hero's, while Saitama accepted all of the teachers.

"I too got bored of it all. I was the best…" Koro-sensei continued the conversation. "Although assassin is a little different then hero." Saitama dropped down to avoid Koro-sensei's next attack and launched a kick towards Koro-sensei's face. Feeling an attack that could kill him approach, Koro-sensei had no choice but to fly upwards or meet his maker. "It was not until I held the only woman I truly loved as she died in my arms… that I realised all my strength, meant nothing."

Saitama leapt into the air. "So what do you suggest?" Saitama was just fast enough to land a punch right into Koro-sensei's gut.

"Find something else." Koro-sensei was lucky. Saitama was too focused on speed with that attack rather than strength, or the octopus would have gone splat. Being the faster of the two, the teacher can avoid most damage, however he also does very little damage. This was going to be a long fight. "I promised that I would look after that class and so I teach."

"So you're saying I should teach?" Saitama blocked the oncoming barrage of tentacles, before feeling one wrap around his leg and slam him into the ground.

"You need to find your own path." Koro-sensei barely dodged Saitama's attack.

This back and forth continued for hours. Neither one was able to get the final blow on the other; however they both were slowly whittled down. Their energy was running out; however they both thoroughly enjoyed this fight. Two equals who do not wish death upon their opponent, fighting for fighting's sake.

Today was a good day for both of them.

XxX

"I believe this is enough."

"Yeah… This is your victory." Saitama lay flat on the ground with the largest grin on his face. He had once again felt the thrill of battle. And even lost. It had been so long since he had last lost. This felt amazing.

"Will you consider what I have spoken about?" Koro-sensei lay nearby. His entire body was intact.

The battle did not come down to stamina, but in the end came down to Saitama's willpower. He could continue this fight for a lot longer, however there was no need. He could not land a decisive blow on his opponent, while he continued to receive them. He had finally given up on trying, even after his entire Serious Series of attacks.

"I will. I'll see you around." Saitama fell asleep where he lay. It was well overdue. Koro-sensei watched as three of his tentacles fell off. He was quickly repairing all the damage done to him, however it was finally over and so he no longer could. He flew away back towards the classroom. He wasn't sure he would be able to wake up if he was attacked after this, so he would need to hide himself. He sincerely hoped he could get through to him.

XxX

Saitama woke up back in his hope. He started getting incredibly annoyed. Was that all another dream? These dreams were going to be the death of him.

"Sensei you're up." Saitama looked up his yellow haired cyborg friend. "I found you in the middle of nowhere all beat, what were you doing there?"

"Ah…" Saitama grinned. That was not a dream. "Oi Genos… I think I'm going to take your training more seriously…"

Genos appeared to be really happy, but Saitama wasn't listening. He was thinking about the a certain teacher and wondered if they would ever meet again.


End file.
